(a) Technical Field of the Invention
The present invention is related to an improved structure of a brake arm in a cantilever brake of a bike, and more particularly to one that is provided with simplified components, fast installation, production cost saving and significant economic benefits.
(b) Description of the Prior Art
Referring to FIG. 1 of the accompanying drawings, a cantilever brake arm 1 of the prior art has inserted to its axle bore 11 a bushing 121 provided with an adjustment base 12. Wherein, the other side of the adjustment base 12 is disposed with a pin 122 to be inserted into a hole 132 provided on one side of a shaft 133 extending from a seat stay 13 of the bike and secured to hold the adjustment base 12 in position. A ring 123 in its diameter greater than that of the bushing 121 is provided at the bottom of the bushing 121 of the adjustment base 12 to merely receive the insertion of a scroll section 141 of a rod spring 14 to be then covered with a cap 15 at the scroll section 141 of the rod spring 14. An adjustment screw 125 is inserted through a folded end 124 of adjustment base 12 to regulate the force of the rod spring 14 by having the adjustment screw 124 to compress against a control section 142 of the rod spring 14. Meanwhile, an inner axle bore 126 in the bushing 121 of the adjustment base 12 is inserted onto the shaft 131 from the seat stay 13 with an end screw 16 inserted into the inner axle bore 133 of the shaft 131 to properly hold against the brake arm 1. However, those many components including the adjustment base 12, the rod spring 14, the cap 15, the brake arm 1 and the end screw 16 in the structure of the brake arm 1 of the prior art arc not tightly constructed, and the assembly of the brake arm 1 is a complicated process involving insertion, alignment, penetration and screw even for a professional worker who is familiar with the assembly process, let alone those in ordinary bike repair shops.